The present invention relates to a shoe and a method of manufacturing same, and more particularly, to a shoe which is used in a swash plate compressor and a method of manufacturing same.
A method of manufacturing a shoe which is used in a swash plate compressor known heretofore is as follows:
Specifically, in a first manufacturing method, a columnar raw material of a given diameter is cut to a given length to provide a disc-shaped raw material, one end face of which is formed with a sintered layer, which is then formed into a sliding surface in the form of a flat plate that is to be disposed in sliding contact with a swash plate. Subsequently, the other end face of the disc-shaped raw material is formed with a spherical recess or a spherical sliding surface comprised of a spherical recess, that is to be disposed in sliding contact with a spherical surface on a piston.
Alternatively, in a second manufacturing method, a steel plate is previously formed with a sintered layer on one of its surfaces, and the plate-shaped raw material is punched into a columnar configuration to provide a columnar raw material. The surface which is provided with the sintered layer is formed into a sliding surface in the form of a flat plate that is to be disposed in sliding contact with a swash plate, while the other end face of the disc-shaped raw material is formed with a spherical recess or a spherical sliding surface comprised of a spherical recess that is to be disposed in sliding contact with a spherical surface on a piston.
The first manufacturing method has an advantage of good material yield because the columnar raw material is cut to a given length to provide the disc-shaped raw material, but has a disadvantage in respect of costs required because the work is complicated because of the need of providing the disc-shaped raw material and then forming the sintered layer thereon.
On the other hand, according to the second manufacturing method, because one surface of the steel plate is formed with the sintered layer, the step of forming the sintered layer is facilitated in comparison to the first manufacturing method, while the plate-shaped raw material which is formed with the sintered layer is punched into the columnar configuration to provide the columnar raw material, thus degrading the material yield to result in a disadvantage in respects of costs required.
In either manufacturing method, the use of the sintered layer resulted in a given limit being placed in improving the performance in respect of seizure resistance.
In view of the foregoing, the present invention provides a shoe and a method of manufacturing same which provide an excellent seizure resistance while allowing its manufacture in an inexpensive manner in comparison to the prior art.
Thus, the present invention relates to a shoe having a flat plate-shaped sliding surface which is adapted to be disposed in sliding contact with a swash plate and a spherical sliding surface which is adapted to be disposed in sliding contact with a spherical surface on a piston;
characterized in that a thermal sprayed layer is formed on the flat plate-shaped sliding surface of the shoe, the surface of the thermal sprayed layer serving as a flat plate-shaped sliding surface.
The present invention also provides a method of manufacturing a shoe which comprises a step of cutting a columnar raw material to a given length to provide a disc-shaped raw material, a step of forming on one end face of the disc-shaped raw material a spherical sliding surface which is adapted to be disposed in sliding contact with a spherical surface on a piston, and a step of forming a thermal sprayed layer on the other end face of the disc-shaped raw material by a H.V.O.F. (High Velocity Oxygen Fuel) spraying process, thus providing the thermal sprayed layer which serves as a flat plate-shaped sliding surface that is adapted to be disposed in sliding contact with a swash plate.
With the manufacturing method mentioned above, the columnar raw material is cut to a given length to provide the disc-shaped raw material, thus achieving a good material yield. In addition, the thermal sprayed layer is formed on the end face of the disc-shaped raw material. As compared with forming a sintered layer according to the prior art, the step of forming the thermal sprayed layer is facilitated, whereby the shoe can be manufactured inexpensively.
A shoe with the thermal flame sprayed layer exhibits a greater seizure resistance than a shoe with a sintered layer, and allows a more reliable operation of a swash plate compressor to be secured, in particular, under an underlubricated condition.
Where the H.V.O.F. spraying process is employed for the thermal spraying, a higher rate of thermal spraying produces a thermal sprayed layer which is more dense and which exhibits a greater strength of adhesion with the columnar raw material, whereby a highly excellent seizure resistance can be expected.